The invention has particular though not exclusive application to recessed lighting fixtures which are commonly mounted in ceilings. Heat tends to build up in the interior of such a fixture, and manufacturers commonly specify with a prominent tag or label the maximum lamp wattage which is recommended for the fixture. Unfortunately, users will often overload a lighting fixture despite the manufacturer's warning, particularly when a lamp of lower, recommended wattage is not available. Such an overload condition can create serious risks of socket burn out and fire.
A commonly adopted protection technique in the case of recessed lighting fixtures is to provide a thermal cut-off in the form of a bi-metalic strip. The bimetalic strip is fixed in thermal communication to the housing of the fixture and serves to discontinue application of line power to the fixture when overheating of the fixture is detected. Such a thermal cut-off is not entirely satisfactory as temperature gradients tend to form over the fixture which may depend in large measure on the surrounding materials. In some applications, the exact location of the bimetalic strip may become critical. Additionally, for many lighting fixtures the use of a bimetalic strip is not convenient, and to the inventor's knowledge there does not appear to be a device available for conveniently handling the problem of fixture overloading.